Boris A. Yurtzev David F. Murray Reidar Elven - Botanical Research ...

18 Journal of the Botanical Research Institute of Texas 6(1)
Fig. 1. Map showing distribution of Ranunculus glacialis subsp. alaskensis.
A. Gray, also based on R. andersonii. The morphological and molecular analyses of Hörandl et al. (2005), Paun
et al. (2005), and Emadzade et al. (2010), using sequences of the matK/trnK and psbJ-petA regions, support
Beckwithia as a genus apart from Ranunculus, but monotypic, consisting only of B. andersonii.
The two northern species of Ranunculus—glacialis and camissonis—have been allied with European species
of sect. Aconitifolii Tutin containing the tall-grown and white-flowered R. aconitifolius L. and R. platanifolius
L., which are confined to montane and subalpine tall-herb communities, and with R. seguieri Vill. and R. kuepferi
Greuter & Burdet, alpine species of scree slopes and margins of snowbeds, respectively. The northern taxa, R.
glacialis and R. camissonis, have a contrasting history, ecology, and distribution, but studies by Paun et al.
(2005) show that the species of section Aconitifolii are phylogenetically coherent.
Ranunculus glacialis and R. camissonis have the following characteristics in common: Perennial plants
with most leaves basal, long-petiolate, with blades deeply trisected or ternately divided (with more or less petiolulate
leaflets in R. glacialis), main segments mostly dissected anew; flowering stems one to several with 2–4
leaves, similar to the basal ones or less divided, and with 1–3 (4) flowers; lower parts of the plant subglabrous
or glabrous, upper parts with peduncles and sepals more or less densely pubescent with dark golden-brown
hairs; petals 5–8, broadly obovate, white, becoming red-tinged and then purple after pollination. Both species
are diploids with 2n = 16. We recognize three taxa: two species, R. camissonis and R. glacialis, the latter with
two infraspecific taxa subsp. glacialis and subsp. alaskensis. Subspecies alaskensis is new to science.